[llvm] [flang][OpenMP] Mark atomic clauses as unique (PR #137460)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-flang-openmp

Author: Krzysztof Parzyszek (kparzysz)

<details>
<summary>Changes</summary>

The current implementation of the ATOMIC construct handles these clauses individually, and this change does not have an observable effect. At the same time these clauses are unique as per the OpenMP spec, and this patch reflects that in the OMP.td file.

---
Full diff: https://github.com/llvm/llvm-project/pull/137460.diff


1 Files Affected:

- (modified) llvm/include/llvm/Frontend/OpenMP/OMP.td (+6-8) 


``````````diff
diff --git a/llvm/include/llvm/Frontend/OpenMP/OMP.td b/llvm/include/llvm/Frontend/OpenMP/OMP.td
index eff6d57995d2b..cdfd3e3223fa8 100644
--- a/llvm/include/llvm/Frontend/OpenMP/OMP.td
+++ b/llvm/include/llvm/Frontend/OpenMP/OMP.td
@@ -602,22 +602,20 @@ def OMP_Assume : Directive<"assume"> {
   ];
 }
 def OMP_Atomic : Directive<"atomic"> {
-  let allowedClauses = [
-    VersionedClause<OMPC_Capture>,
-    VersionedClause<OMPC_Compare, 51>,
-    VersionedClause<OMPC_Read>,
-    VersionedClause<OMPC_Update>,
-    VersionedClause<OMPC_Write>,
-  ];
   let allowedOnceClauses = [
     VersionedClause<OMPC_AcqRel, 50>,
     VersionedClause<OMPC_Acquire, 50>,
+    VersionedClause<OMPC_Capture>,
+    VersionedClause<OMPC_Compare, 51>,
     VersionedClause<OMPC_Fail, 51>,
     VersionedClause<OMPC_Hint, 50>,
+    VersionedClause<OMPC_Read>,
     VersionedClause<OMPC_Relaxed, 50>,
     VersionedClause<OMPC_Release, 50>,
     VersionedClause<OMPC_SeqCst>,
+    VersionedClause<OMPC_Update>,
     VersionedClause<OMPC_Weak, 51>,
+    VersionedClause<OMPC_Write>,
   ];
   let association = AS_Block;
   let category = CA_Executable;
@@ -668,7 +666,7 @@ def OMP_CancellationPoint : Directive<"cancellation point"> {
   let category = CA_Executable;
 }
 def OMP_Critical : Directive<"critical"> {
-  let allowedClauses = [
+  let allowedOnceClauses = [
     VersionedClause<OMPC_Hint>,
   ];
   let association = AS_Block;

``````````

</details>


https://github.com/llvm/llvm-project/pull/137460